Electrochemical battery packs are used to energize electric machines in a variety of systems. For instance, motor output torque from a rotor shaft of an electric machine in the form of a traction motor or motor/generator unit may be transmitted to an input member of a transmission. The motor output torque in such a configuration may be used to perform useful work as part of a mobile or stationary power plant or other torque-generating system. The electric machine may be an alternating current (AC) or direct current (DC) device that draws electrical energy from or delivers electrical energy to the various cells of the battery pack as needed. In turn, the battery pack may be recharged via a charging current supplied from an offboard power supply or onboard regeneration. The battery cells store an electric charge until needed, while a reverse reaction discharges the battery cells to deliver electricity to the windings of the electric machine. The charging and discharging currents, as well as the individual cell voltages, are closely monitored and regulated by a master battery control module so as to optimize overall system performance.
Battery packs, particularly those used as a DC power supply in a hybrid electric or battery electric vehicle, may have a modular design. That is, a predetermined number of battery cells may be stacked together within an outer cage, with multiple modular housings serially connected to form a battery pack of a desired size. The battery cells may be interconnected via a flexible or rigid interconnect member and enclosed using a module cover or other suitable enclosure in order to protect the battery cells from moisture, dirt, and other debris.
In some configurations, each battery pack may have a resident master controller referred to as a battery system manager (BSM). The BSM is typically directly mounted to the battery pack. Each battery module includes a dedicated cell sensing board (CSB) in the form of an integrated circuit. The CSB is configured to read the individual battery cell voltages for a given battery module and report the cell voltages to the BSM as part of the overall battery control strategy. The various CSBs are typically connected in a daisy-chain manner to the resident BSM via cables, harnesses, and other physical connectors to provide the requisite communications and electrical connectivity.